Numerical Study of the Hydrodynamic Pressure Field Generated due to Ship Motion at Different Speeds

Ship movement in the shallow seas creates a significant hydrodynamic pressure field about the ship that has effect on the environmental structures such as waterway beds, stationary or moving neighbored vessels, and can also affect marine life. Therefore, the study of this phenomenon is very important in many applications. The present study investigated the hydrodynamic pressure field caused by an oil tanker with ۲۴۷ m long, ۵۳ m wide and ۱۷ m draft moving at different speeds of ۱۰, ۱۵ and ۲۰ knots on a sea level with a depth of ۸۰ m. The fluid flow governing equations including the continuity equation, the momentum equations, and the K-ε turbulence model are solved numerically and the SIMPLE algorithm is used to correlate the pressure and velocity fields. An accurate Trimmer's structured mesh has been utilized to discrete the studied domain around the ship. To validate the methodology, the obtained dimensionless velocity field is compared with those presented by other works a good consistency is observed. As expected, the magnitude of the hydrodynamic pressure field varied as a function of the distance to the body of the vessel, ship's traveling velocity and magnitude of the draft. In this study, the minimum effects of the pressure were for the case of ۱۰ knots (the minimum working velocity of heavy vessels) and ۸۰ m of depth with a maximum pressure of ۹۸۰ Pa. The results show that the pressure field dissipation occurs more rapidly in close distances to the vessel, and the pressure field domain decreases with a lower slope in far away from of the body. a hydrodynamic pressure correlation is obtained based on the depth and ship's velocity. Two and three-dimensional hydrodynamic pressure contours are also presented for different depths and velocities. Moreover, he hydrodynamic pressure increments in ۱۲ and ۷ m drafts are investigated and that shows after the ۳/۴ height of the bulbous bow lies below the sea surface, the increase in draft has little effect on the hydrodynamic pressure field.

Keywords:

Hydrodynamic pressure field , Draft , Oil tanker , CFD